STL - Lambert-St. Louis International Airport, St Louis, United States

A Postal Service drop box for first class (letters) mail is located in the lower level of Terminal 1 between doors 17 and 18. The last collection of mail from this drop box is 4:30 p.m., Monday through Friday.
Stamps may be purchased at the US Bank ATM machine located next to the US Bank Branch, Lower Level of Terminal 1.